Disrupted zinc-binding sites in structures of pathogenic SOD1 variants D124V and H80R.

Sai V. Seetharaman, Duane D. Winkler, Alexander B. Taylor, Xiaohang Cao, Lisa J. Whitson, Peter A. Doucette, Joan S. Valentine, Virgil Schirf, Borries Demeler, Mark C. Carroll, Valeria C. Culotta, P. John Hart

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

Mutations in human copper-zinc superoxide dismutase (SOD1) cause an inherited form of the fatal neurodegenerative disease amyotrophic lateral sclerosis (ALS). Here, we present structures of the pathogenic SOD1 variants D124V and H80R, both of which demonstrate compromised zinc-binding sites. The disruption of the zinc-binding sites in H80R SOD1 leads to conformational changes in loop elements, permitting non-native SOD1-SOD1 interactions that mediate the assembly of these proteins into higherorder filamentous arrays. Analytical ultracentrifugation sedimentation velocity experiments indicate that these SOD1 variants are more prone to monomerization than the wild-type enzyme. Although D124V and H80R SOD1 proteins appear to have fully functional copper-binding sites, inductively coupled plasma mass spectrometery (ICP-MS) and anomalous scattering X-ray diffraction analyses reveal that zinc (not copper) occupies the copper-binding sites in these variants. The absence of copper in these proteins, together with the results of covalent thiol modification experiments in yeast strains with and without the gene encoding the copper chaperone for SOD1 (CCS), suggests that CCS may not fully act on newly translated forms of these polypeptides. Overall, these findings lend support to the hypothesis that immature mutant SOD1 species contribute to toxicity in SOD1-linked ALS.

Original languageEnglish (US)
Pages (from-to)5714-5725
Number of pages12
JournalBiochemistry
Volume49
Issue number27
DOIs
StatePublished - Jul 13 2010

ASJC Scopus subject areas

  • Biochemistry

Fingerprint Dive into the research topics of 'Disrupted zinc-binding sites in structures of pathogenic SOD1 variants D124V and H80R.'. Together they form a unique fingerprint.

Cite this